This invention relates to the upgrading of a petroleum oil containing metallic contaminants by contacting the oil with an aqueous solution of ferric salts and/or stannic chloride.
In catalytic cracking, it has been known for sometime that certain metals, particularly vanadium and nickel, are very harmful to cracking catalysts. When deposited on cracking catalysts in concentrations of about 0.1 weight percent or less, such metals cause the production of extensive amounts of coke and gas at the expense of valuable gasoline and heating oil fractions. This leads to a number of problems, including overloading of the regeneration and gas handling equipment and reducing the effective life of the catalyst and the like.
Metal contaminants also cause severe problems in hydrodesulfurizing hydrocarbon residua. The catalyst life is metals-limited in typical residua desulfurizing processes. Usually, metal contaminants reduce the life of the catalyst by as much as one-half compared to the case where the feed is free of these contaminants.
Vanadium and/or nickel is brought into a processing unit along with the other unfilterable metallic impurities present in the petroleum oil. Usually these impurities are metal salts of organic compounds, asphaltene-metal complexes, porphyrin-type metal complexes and the like normally present in petroleum oils. The substantial removal of these metal contaminants from petroleum oil is the concern of the present invention.